1. Technical Field
The present invention relates to an intrusion detection system. In the particular, the present invention relates to a vehicle intrusion detection system that employs a linear imager to image a limited portion of the vehicle interior.
2. Description of the Prior Art
It is known to provide an intrusion detection system for a vehicle, such as an automobile. One type of known system includes a camera that is operative to take pictures (images) of the interior of the vehicle, in order to detect an intrusion into the vehicle. Another type of system uses ultrasonic sensing.
An intrusion detection system should have low power consumption, so that the vehicle battery is not drained when the alarm system is operated for a long period of time without the vehicle engine running. A typical visual light based system illuminates the entire vehicle interior, thereby drawing a large amount of power. In addition, false alarms should be minimized. For example, an ultrasonic system may give a false alarm if the vehicle window is at least partially open and an object comes near to, but does not enter, the vehicle occupant compartment. A visual light based system can be susceptible to variations in ambient lighting, particularly to moving shadows cast by objects outside of the vehicle and provide a false alarm.